Nanoporous microneedle arrays seamlessly connected to a drug reservoir for tunable transdermal delivery of memantine

Quantitative evaluation of accelerated transdermal drug delivery by electroosmosis via frustoconical porous microneedles

Electroosmosis-based transdermal drug delivery via frustoconical porous microneedles (F-PMNs) is studied by quantitative fluorescence analysis of the drug models penetrated into excised pig skin. An array of 300 μm height F-PMN made of poly-glycidyl methacrylate is modified by a grafted thin film of anionic poly (2-acrylamido-2-methylpropanesulfonic acid) (PAMPS) or a cationic poly-(3-acrylamidopropyl trimethylammonium) (PAPTAC) to generate electroosmotic flow (EOF) upon application of current through the needles. Owing to the synergy of the EOF-promoted transport and the expansion of the stratum corneum with the frustoconical protrusions, the penetration rates of rhodamine B (479 Da) and FITC-dextran (4 kDa and 10 kDa) are found to be accelerated by more than 10 times. In addition, the F-PMNs modified with PAMPS and PAPTAC show similar delivery rates in opposite directions, enabling the possible dual-mode delivery from both anode and cathode in an integrated iontophoresis device.

Development and Validation of a Simple UV-HPLC Method to Quantify the Memantine Drug Used in Alzheimer's Treatment

Memantine, a non-competitive NMDA receptor antagonist, is used to treat Alzheimer's disease. Therefore, loading memantine in nanoparticles (NPs) could be an essential tool to improve the treatment effectiveness while reducing drug toxicity. Even though some approaches have been described to quantify memantine, none reported optimized methods using high-performance liquid chromatography resorting to ultraviolet detection (UV-HPLC) to determine encapsulation in NPs. The present research developed a HPLC method using pre-column derivatization for quantitatively analyzing memantine hydrochloride in NPs. Memantine was derivatized using 9-fluorenylmethyl chloroformate (FMOC). The developed method was fully validated regarding suitability, specificity, linearity, sensitivity, precision, accuracy, and robustness according to the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use guidelines. The retention time of memantine was 11.393 ± 0.003 min, with a mean recovery of 92.9 ± 3.7%. The new chromatographic method was validated and found to respond linearly over 5-140 μg/mL, with a high coefficient of determination. Intraday precision lay between 3.6% and 4.6%, and interday precision between 4.2% and 9.3%. The stability of memantine was also tested at 4 °C and -20 °C, and no signs of decay were found for up to 6 months. The new method was properly validated and proved simple, sensitive, specific, accurate, and precise for determining memantine encapsulation efficiency in lipid NPs. Greenness was evaluated, presenting a final score of 0.45. In the future, this methodology could also be applied to quantify memantine in different nanoformulations.

Translation from Preclinical Research to Clinical Trials: Transdermal Drug Delivery for Neurodegenerative and Mental Disorders

Neurodegenerative diseases (NDs), particularly dementia, provide significant problems to worldwide healthcare systems. The development of therapeutic materials for various diseases has a severe challenge in the form of the blood-brain barrier (BBB). Transdermal treatment has recently garnered widespread favor as an alternative method of delivering active chemicals to the brain. This approach has several advantages, including low invasiveness, self-administration, avoidance of first-pass metabolism, preservation of steady plasma concentrations, regulated release, safety, efficacy, and better patient compliance. Topics include the transdermal method for therapeutic NDs, their classification, and the mechanisms that allow the medicine to enter the bloodstream through the skin. The paper also discusses the obstacles and potential outcomes of transdermal therapy, emphasizing the benefits and drawbacks of different approaches.

Dual engine-driven bionic microneedles for early intervention and prolonged treatment of Alzheimer's disease

The microneedle (MN) delivery system presents an attractive administration route for patients with Alzheimer's disease (AD). However, the passive drug delivery mode and low drug loading of MNs often result in unsatisfactory therapeutic efficiency. To address these dilemmas, we developed dual engine-drive bionic MNs for robust AD treatment. Specifically, free rivastigmine (RVT) and RVT particles were co-loaded within the MNs to construct the valve and chambers of the guava, respectively, which can serve as an active engine to promote drug permeation by generating capillary force. K2CO3 and citric acid were introduced as a pneumatic engine into the MNs to promote the permeation of free RVT into deeper skin layers for early intervention in AD. Further, the RVT particles served as a drug depot to provide continuous drug release for prolonged AD treatment. Compared with free RVT-loaded MNs, the dual engine-driven bionic MNs showed an increase in drug loading, cumulative transdermal permeability, and normalized bioavailability of approximately 40%, 22%, and 49%, respectively. Pharmacodynamic studies further confirmed that the dual engine-driven bionic MNs were most effective in restoring memory and recognition functions in mice with short-term memory dysfunction. Therefore, the dual engine-driven bionic MNs hold great promise for highly efficient AD treatment.

Strategies to develop polymeric microneedles for controlled drug release

The remarkable appeal of microneedle controlled-release systems has captivated both the academic community and pharmaceutical industry due to their great potential for achieving spatiotemporally controlled release, coupled with their the minimally invasive nature and ease of application. Over the years, scientists have dedicated their efforts to advancing microneedle systems by manipulating the physicochemical properties of matrix materials, refining microneedle designs, and interfacing with external devices to provide tailored drug release profiles in a spatiotemporally controllable manner. Expanding upon our understanding of drug release mechanisms from polymeric microneedles, which include diffusion, swelling, degradation, triggering, and targeting, there is a growing focus on manipulating the location and rate of drug release through innovative microneedle designs. This burgeoning field of microneedle-based drug delivery systems offers further prospects for precise control over drug release. The design strategies of polymeric microneedle systems for temporally controlled and locally targeted release, as well as the delivery mechanisms by which drugs can be released from a microneedle system are critically reviewed in this work. Furthermore, this review also puts forward some perspectives on the potential and challenges involved in translating these microneedle-based delivery systems into the next generation therapies.

Microneedles as a momentous platform for psoriasis therapy and diagnosis: A state-of-the-art review

Psoriasis is a chronic, autoimmune, and non-communicable skin disease with a worldwide prevalence rate of 2-3%, creating an economic burden on global health. Some significant risk factors associated with psoriasis include genetic predisposition, pathogens, stress, medications, etc. In addition, most patients with psoriasis should also deal with comorbidities such as psoriatic arthritis, inflammatory bowel diseases, cardiovascular diseases, and psychological conditions, including suicidal thoughts. Based on its severity, the treatment approach for psoriasis is categorised into three types, i.e., topical therapy, systemic therapy, and phototherapy. Topical therapy for mild-to-moderate psoriasis faces several issues, such as poor skin permeability, low skin retention of drug formulation, greasy texture of topical vehicle, lack of controlled release, and so on. On the other arrow, systemic therapy via an oral or parenteral route of drug administration involves numerous drawbacks, including first-pass hepatic metabolism, hepatotoxicity, gastrointestinal disturbances, needle pain and phobia, and requirement of healthcare professional to administer the drug. To overcome these limitations, researchers devised a microneedle-based drug delivery system for treating mild-to-moderate and moderate-to-severe psoriasis. A single microneedle system can deliver the anti-psoriatic drugs either locally (topical) or systemically (transdermal) by adjusting the needle height without involving any pain. In this contemplate, the current review provides concise information on the pathophysiology, risk factors, and comorbidities of psoriasis, followed by their current treatment approaches and limitations. Further, it meticulously discusses the potential of microneedles in psoriasis therapy and diagnosis, along with descriptions of their patents and clinical trials.

Frustoconical porous microneedle for electroosmotic transdermal drug delivery

A truncated cone-shaped porous microneedle (PMN) made of poly-glycidyl methacrylate was studied as a minimally invasive tool for transdermal drug delivery. The transdermal electrical resistance of a pig skin was evaluated during the indentation of the PMNs, revealing that the frustoconical PMN (300 μm height) significantly reduced the resistance of the skin by expanding the stratum corneum without penetrating into the skin. A thin film of poly (2-acrylamido-2-methylpropanesulfonic acid) (PAMPS) was grafted onto the inner wall of the microchannels of the frustoconical PMN to generate electroosmotic flow (EOF) upon current application in the direction of injection of the drug into the skin. Owing to the synergy of the expansion of the stratum corneum and the EOF-promotion, the PAMPS-modified frustoconical PMN effectively enhances the penetration of larger (over 500 Da) molecules, such as dextran (∼10 kDa).

Drug Delivery Systems as a Strategy to Improve the Efficacy of FDA-Approved Alzheimer's Drugs

Alzheimer's disease (AD) is the most common form of dementia, with a high impact worldwide, accounting for more than 46 million cases. The continuous increase of AD demands the fast development of preventive and curative therapeutic strategies that are truly effective. The drugs approved for AD treatment are classified into acetylcholinesterase inhibitors and N-methyl-D-aspartate receptor antagonists. The therapeutic effectiveness of those drugs is hindered by their restricted access to the brain due to the blood-brain barrier, low bioavailability, and poor pharmacokinetic properties. In addition, the drugs are reported to have undesirable side effects. Several drug delivery systems (DDSs) have been widely exploited to address these issues. DDSs serve as drug carriers, combining the ability to deliver drugs locally and in a targeted manner with the ability to release them in a controlled and sustained manner. As a result, the pharmacological therapeutic effectiveness is raised, while the unwanted side effects induced by the unspecific distribution decrease. This article reviews the recently developed DDSs to increase the efficacy of Food and Drug Administration-approved AD drugs.

Overcoming skin barriers through advanced transdermal drug delivery approaches

Upon exhaustive research, the transdermal drug delivery system (TDDS) has appeared as a potential, well-accepted, and popular approach to a novel drug delivery system. Ease of administration, easy handling, minimum systemic exposure, least discomfort, broad flexibility and tunability, controlled release, prolonged therapeutic effect, and many more perks make it a promising approach for effective drug delivery. Although, the primary challenge associated is poor skin permeability. Skin is an intact barrier that serves as a primary defense mechanism to preclude any foreign particle's entry into the body. Owing to the unique anatomical framework, i.e., compact packing of stratum corneum with tight junction and fast anti-inflammatory responses, etc., emerged as a critical physiological barrier for TDDS. Fusion with other novel approaches like nanocarriers, specially designed transdermal delivery devices, permeation enhancers, etc., can overcome the limitations. Utilizing such strategies, some of the products are under clinical trials, and many are under investigation. This review explores all dimensions that overcome poor permeability and allows the drug to attain maximum potential. The article initially compiles fundamental features, components, and design of TDDS, followed by critical aspects and various methods, including in vitro, ex vivo, and in vivo methods of assessing skin permeability. The work primarily aimed to highlight the recent advancement in novel strategies for effective transdermal drug delivery utilizing active methods like iontophoresis, electroporation, sonophoresis, microneedle, needleless jet injection, etc., and passive methods such as the use of liposomes, SLN, NLC, micro/nanoemulsions, dendrimers, transferosomes, and many more nanocarriers. In all, this compilation will provide a recent insight on the novel updates along with basic concepts, the current status of clinical development, and challenges for the clinical translation of TDDS.

A Semi-Dissolving Microneedle Patch Incorporating TEMPO-Oxidized Bacterial Cellulose Nanofibers for Enhanced Transdermal Delivery

Although dissolving microneedles have garnered considerable attention as transdermal delivery tools, insufficient drug loading remains a challenge owing to their small dimension. Herein, we report a one-step process of synthesizing semi-dissolving microneedle (SDMN) patches that enable effective transdermal drug delivery without loading drugs themselves by introducing TEMPO-oxidized bacterial cellulose nanofibers (TOBCNs), which are well dispersed, while retaining their unique properties in the aqueous phase. The SDMN patch fabricated by the micro-molding of a TOBCN/hydrophilic biopolymer mixture had a two-layer structure comprising a water-soluble needle layer and a TOBCN-containing insoluble backing layer. Moreover, the SDMN patch, which had a hole in the backing layer where TOBCNs are distributed uniformly, could offer novel advantages for the delivery of large quantities of active ingredients. In vitro permeation analysis confirmed that TOBCNs with high water absorption capacity could serve as drug reservoirs. Upon SDMN insertion and the application of drug aqueous solution through the drug inlet hole, the TOBCNs rapidly absorbed the solution and supplied it to the needle layer. Simultaneously, the needle layer dissolved in body fluids and the drug solution to form micro-channels, which enabled the delivery of larger quantities of drugs to the skin compared to that enabled by solution application alone.